JPH05251717A - Semiconductor package and semiconductor module - Google Patents

Abstract

PURPOSE:To provide a means for applying a practical optical interconnection technique to the input and output of signals of semiconductor package and semiconductor module. CONSTITUTION:A semiconductor package mounting a wiring substrate 20 loaded with semiconductor chips 10 is equipped with an optical element 30 having a wiring layer 22 in common with the wiring substrate 20 on a surface and also equipped with an optical transmission medium 40 and receptacle 50, with which an optical fiber connector 60 is connected, in a package base 80, in which the wiring substrate 20 is installed. Thus, input and output signals can be taken out from the package base with high density, a signal transmission between packages can be performed at higher speed than that in the case of an electric signal, and it can be contrived to make the performance of a system composed of a plurality of semiconductor packages higher.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor package and a semiconductor module, and more particularly to a semiconductor package and a semiconductor module to which an optical interconnection technique is applied for signal input / output.

[0002]

2. Description of the Related Art In recent years, as semiconductor chips have been highly integrated and operated at high speed, there has been a demand for improvement in mounting density and wiring density in semiconductor packages. As a powerful mounting method for this requirement, the technology known in the past includes:
For example, as described in JP-A-62-73651, there is a silicon-on-silicon package in which a semiconductor chip is flip-chip connected to a wiring board made of a semiconductor wafer. This mounting method can increase the mounting density as compared with the mounting method in which the semiconductor chips are individually packaged, and it is possible to form high-density wiring on the surface of the wiring board by the same process as the semiconductor chip. is there. In addition, the semiconductor chip and the wiring board can be connected at high density by connecting using solder bumps.

However, in the above mounting method, the number of input / output pins that can be taken out from the package base is limited. That is, the input / output pins of the wiring board are connected to the package base by wire bonding or TAB (tape automated bonding) around the wiring board, or by feedthrough penetrating the wiring board. Therefore, the number of input / output pins that can be taken out from the package base is limited by the wiring and the pitch of the input / output pins themselves.

The pitch of the bonding wires and TAB is
For example, in "Bare Chip Mounting Centering on COB and TAB Mounting-Latest Technology Development and Reliability Measures (1990)" published by the Technical Information Institute, pp. 285 to 28.
As described on page 7, it is limited by the reliability of the connection, and the limits are about 150 μm and 80 μm, respectively. Further, since the connection of the wiring to the bonding wire or the TAB is performed around the wiring board, the wiring length of the signal wiring becomes long and the connection point from the semiconductor chip to the periphery of the wiring board, that is, the bonding wire or the TAB lead. The problem is that the signal propagation delay time up to is increased.

On the other hand, the feedthrough is formed on the wiring substrate by thermomigration or anisotropic etching, as described in, for example, Japanese Patent Laid-Open No. 62-73651. The pitch of the feedthrough is limited depending on the thickness of the wiring board. In the case of a feedthrough, its pitch can be set to several hundreds of μm, but it is not generally used at present because a potential application and an insulating film are required to insulate the feedthrough.

[0006] The package-based input / output pin pitch is, for example, "Proceedings of 41s" (Proceedings of 41s).
t Electronic Components & Technology Conference (19
91)) ”As described on pages 234 to 244, it is limited by the structure of the pins provided on the package base and the connector on the wiring board, and its electrical characteristics. In particular, the connector provided on the wiring board requires a spring mechanism for contacting the pin and the connector and a mechanism for reducing the insertion force into the pin, so there is a mechanical limit to miniaturization of the pin and the connector. .. Further, if the pin pitch is narrowed, crosstalk and inductance increase, and there is an electrical limit particularly when inputting and outputting a high speed signal. Therefore, the pitch of the input / output pins is limited to about 2 mm in the face-centered lattice arrangement. In addition, in the above literature, a spring-shaped connector having a special shape or a connector similar to TAB is proposed as a substitute for the input / output pin. In this spring type connector, the pitch can be about 1 mm. However, these are not generally used because mechanical strength and reliability are not yet guaranteed like the conventional input / output pins. Further, in the TAB type connector, since the wiring is taken out from around the package base as in the conventional TAB, the signal delay time in the base becomes a problem.

[0007]

The multiple input / output of semiconductor packages is an important issue. In particular, in order to configure a large-scale information processing system or the like with a large number of highly integrated packages, it is necessary to connect the packages with a large number of wirings.

For example, assume here a silicon-on-silicon package in which an instruction processor circuit chip and a system control circuit chip are mounted. When a multiprocessor system is constructed using N such semiconductor packages, an interconnection network between these N semiconductor packages (= between system control circuit chips) holds the key to system performance. A fully connected network is desirable for the highest performance. The total number of wires in the complete connection network is
Since it is proportional to N × (N−1), the number of wires in such a system becomes enormous. For example, assuming that N = 8 and the packages are connected by wiring of 64 bytes, the total number of wirings is about 57,000, and about 7,000 input / output pins are required per package. Assuming an appropriate package size of several inches square,
The number of input / output pins that can be taken out from this package is limited to about 1000 at most due to the above-mentioned limitation. Therefore, in the conventional technology, it was not possible to construct the most ideal complete connection network in such a system.

Although the above example is for a multiprocessor system, there is a similar problem in the case of the prior art in an information processing system such as a massively parallel processor or a large capacity exchange. That is, the performance of the semiconductor package has been hindered by the limit of the number of input / output pins of the semiconductor package.

As a means for solving such an input / output pin neck, optical interconnection is considered promising.
In general, optical interconnection is
Since it has advantages such as no crosstalk or ground noise, no deterioration of signal waveform, and high-speed / broadband transmission, it is said that wiring with higher density than electrical wiring is possible. Conventionally known optical interconnection technology is, for example, the technology described in JP-A-63-502315. In this technique, a semiconductor chip and an optical element are connected to a stacked semiconductor wafer, and wiring is provided between the wafers by light penetrating the wafers.

However, the above technique does not take into consideration the method of supplying power to the semiconductor wafer, the arrangement of the optical elements on the semiconductor wafer, the cooling of the semiconductor chip in the package, the means for inputting / outputting the optical signal from the package, and the like. Therefore, such optical interconnection technology cannot be applied as it is as a means for solving the input / output pin neck of the semiconductor package. When flip-chip connecting an optical element to a semiconductor wafer, there arises a problem that the packaging density of the semiconductor chips decreases. Further, the process of monolithically forming an optical element on a semiconductor wafer is very difficult, and there is a problem that the optical element is deteriorated due to a difference in thermal expansion between the optical element and the semiconductor wafer. Further, since a high-speed and highly integrated semiconductor chip generates a large amount of heat, it has been disclosed in JP-A-62-62
It is necessary to provide cooling on the package cap side as described in No. 73651. For this reason, if an optical signal is input / output on the side surface of the package as described in, for example, JP-A-63-237486, it is necessary to provide an input / output space around the package so as not to hinder cooling. There is a problem that the packaging density of the package on the wiring board is reduced. Therefore, it can be said that the input / output of the optical signal is preferably performed on the package base.

As a means for inputting / outputting an optical signal in the package base, an optical element package as described in JP-A-64-30274 is known. This technology fixes the optical fiber to the through hole provided in the package base,
The optical element is flip-chip connected to face the optical fiber.

However, since this technique does not take into consideration the arrangement of optical elements, the handling of optical fibers, the cooling of optical elements, etc., it cannot be applied to a semiconductor package as it is. Alternatively, if the optical element is flip-chip connected to the wiring board together with the semiconductor chip, there arises a problem that the mounting density of the semiconductor chip decreases. Since the optical fiber is always fixed to the package base, there is a problem that it is very inconvenient to handle the optical fiber and insert / remove the input / output pin. Further, since an optical element such as a semiconductor laser used for high speed transmission has a large temperature dependency, it is necessary to sufficiently radiate heat.

As described above, in order to apply the optical interconnection technology to the high speed / highly integrated semiconductor package, the optical signal input / output means to / from the package is required.
It is necessary to comprehensively consider the mounting density of semiconductor chips, arrangement of optical elements, cooling means for semiconductor chips and optical elements, package mounting density on wiring boards, and handling of input / output pins and optical fibers.

Therefore, an object of the present invention is to make it possible to apply the optical interconnection technology to a high speed / highly integrated semiconductor package by considering the above contents.
An object of the present invention is to provide means for solving the input / output pin neck in a highly integrated semiconductor package.

Another object of the present invention is to provide an optical signal wiring means inside and outside the semiconductor module in a semiconductor module in which a semiconductor package to which the optical interconnection technique is applied is mounted on a wiring board.

Still another object of the present invention is to provide means for forming a multiprocessor with this semiconductor module.

[0018]

In order to achieve the above-mentioned object, the present invention provides a semiconductor package comprising a semiconductor chip and a wiring board, which comprises an optical element having a wiring layer common to the wiring board on the surface thereof. The package base to be installed is provided with a light propagation medium, and the package base is provided with a receptacle for connecting the light propagation medium and the optical fiber connector.

In order to achieve the above-mentioned other object, the present invention provides a semiconductor module, in which a package base is provided with input / output pins and receptacles for optical fiber connectors, and an input / output pin connector is provided on the surface of a wiring board. An optical fiber connector installed on a wiring board so that an optical axis is perpendicular to the board is provided, and an optical fiber connected to the optical fiber connector is laid on the back surface of the wiring board.

Further, in order to form a multiprocessor system with such a semiconductor module, a wiring board made of a semiconductor wafer is provided, and a semiconductor chip or a wiring board formed on an instruction processor circuit and a system control circuit is provided, and a wiring layer is provided. A plurality of semiconductor packages in which an instruction processor circuit or a system control circuit and an optical element are connected are mounted on a wiring board, and the plurality of semiconductor packages are connected by an optical fiber laid on the back surface of the wiring board.

[0021]

By the above means, the semiconductor chip and the optical element can be connected by the wiring layer, and the light emitted or received by the optical element can be connected to the optical fiber outside the package through the optical propagation medium and the optical connector. That is, optical input / output can be performed in the package base. Since the optical element has the same wiring layer as the wiring board, the semiconductor chip and the optical element can be arranged close to each other, and the wiring delay time between the semiconductor chip and the optical element can be shortened. Also,
Since the optical element and the wiring board are configured in a hybrid manner, it is possible to avoid the problems of process difficulty and deterioration of the optical element due to the difference in thermal expansion of the constituent materials as in the case of monolithic formation. Further, the semiconductor chip can be cooled on the package cap side. Unlike the case where optical input / output is performed on the side surface of the package, the package mounting density on the wiring board does not decrease. Since the optical fiber connector can be detached from the package base, handling is not as inconvenient as when the optical fiber is fixed to the package base.

Further, by mounting a semiconductor package to which the optical interconnection technology is applied on a wiring board, both optical input / output and electrical input / output can be taken out from the package base, and the characteristics of signals connecting between semiconductor packages can be obtained. Accordingly, it is possible to perform appropriate signal transmission.

Furthermore, by mounting a semiconductor chip or a semiconductor wafer on which an instruction processor circuit and a system control circuit are formed in a semiconductor package, a multiprocessor system with a high-density optical fiber connection network can be easily constructed.

[0024]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a semiconductor package according to the first embodiment of the present invention. In FIG. 1, a plurality of semiconductor chips 10 are mounted on a wiring board 20, and the wiring board 20 is further mounted on a package base 80. The wiring board 20 is provided with an optical element 30 that shares the multilayer wiring layer 22. Further, the package base 80 on which the wiring board 20 is installed is provided with a light propagation medium 40 for transmitting an optical signal from the optical element 30, and further, a receptacle for connecting the light propagation medium 40 and the optical fiber connector 60. 50 are provided. The components of the semiconductor package according to this embodiment will be described below.

The semiconductor chip 10 is made of Si and has a chip size of about 2 cm square. An integrated circuit 11 is formed on the semiconductor chip 10. The semiconductor chip 10 and the wiring board 20 are connected by solder bumps 12. The solder bumps 12 are made of Pb-Sn based solder, and their arrangement pitch is 250 μm.

The wiring board 20 is made of Si similarly to the semiconductor chip 10 and has a wafer size of about 3 inches square. An integrated circuit 21 is formed on the wiring board 20, and an optical element 30 is provided. Wiring board 20
A common multilayer wiring layer 22 is formed on the surface of the optical element 30 and the surface of the optical element 30. The multilayer wiring layer 22 is made of Cu / A, for example.
1 / polyimide. The integrated circuit 11 or 21 is electrically connected to the package base 80 by the multilayer wiring layer 22 and the TAB 23, or the multilayer wiring layer 2
Wirings 24, 25, etc. in 2 are connected to individual light emitting portions or light receiving portions 31 of the optical element 30. The wiring pitch of the TAB 23 is 100 μm. In addition, the integrated circuit 11,
In order to reduce the wiring delay time between the optical element 21 and the optical element 30, the optical element 30 is provided near the center of the wiring board 20. The wiring board 20 is fixed to the package base 80 by a heat conductive resin, and the heat generated in the integrated circuit 21 and the optical element 30 is radiated through the package base 80.

The optical element 30 is made of, for example, an InP-based semiconductor, and the light emitting / receiving portion 31 is made of a surface emitting laser diode or a pin photodiode. In this embodiment, the optical elements 30 are integrated in a two-dimensional array,
The array pitch is 250 μm, and the oscillation light wavelength or the light reception wavelength is 1.3 μm. The light emitting and receiving portions 31 are separated by grooves 32 in order to prevent optical or thermal crosstalk.

The optical element 30 is fixed by a polyimide resin 33 into a through hole provided in the wiring board 20 by a processing method such as etching or dicing. The drive circuit of the optical element 30 is formed in the optical element 30 itself or in the integrated circuits 11 and 21 near the optical element 30. In this embodiment, the integrated circuits 11 and 21 and the optical element 30 are used.
Are connected by the common multilayer wiring layer 22 on the surface of the wiring substrate 20 and the optical element 30, as described above. Therefore, unlike the case where the optical element 30 is flip-chip connected onto the wiring board 20, the mounting density of the semiconductor chips 10 is not reduced, and the optical element 30 provided separately from the wiring board 20 is wire-bonded or bonded. Finer and more complicated wiring can be performed as compared with the case of connecting by TAB.

The package base 80 is made of a mullite ceramic multilayer wiring board, and in this embodiment, the board size is about 3.5 inch square. Package base 80
The optical transmission medium 40, the receptacle 50, and the input / output pin 81 are provided in. The TAB 23 is connected to the input / output pin 81 provided on the lower surface of the package base 80 by the wiring inside the package base 80. The input / output pins 81 are arranged in a face-centered grid pattern with an arrangement pitch of 2 mm.

The light propagating medium 40 is made of, for example, silica glass, and has a surface for reducing optical coupling loss.
The lenses 41 are formed in a two-dimensional array by a processing method such as etching. The structure and arrangement of the lens can be changed depending on the optical design. For example, a grating lens, a gradient index lens or the like may be used. The array pitch is 250 μm like the optical element 30. By thus forming the lens 41 on the light propagation medium 40, the optical coupling loss between the optical element 30 and the optical fiber 70 can be reduced, and the optical crosstalk can be reduced. When it is necessary to further reduce optical crosstalk, it is effective to provide a light shielding element between adjacent optical paths.

The light propagation medium 40 is sealed and fixed by a low melting point glass 42 in a through hole provided in the package base 80 in advance. The optical fiber 70 is directly fixed to the package base 80 by sealingly fixing the light propagation medium 40 to the package base 80 with the low melting point glass 42.
Not only is the sealing work easier than sealing and fixing, but the optical fiber 70 can be attached to and detached from the package base 80, and the package after sealing and fixing can be handled easily. it can.

The receptacle 50 is made of a resin precision molded product and is provided with a connector pin 51. The receptacle 50 is fixed to the package base 80 with a resin or the like having high adhesive strength.

Further, the package base 80 is provided on its upper surface with a frame 82 and a cap 83 for protecting the wiring substrate 20 and the semiconductor chip 10 mounted on the package base 80 from the external atmosphere. The frame 82 and the cap 80 are made of, for example, Kovar alloy. The frame 82 is a package base 80
Is fixed to the periphery of the upper surface of the frame by a brazing material, and the cap 83 is seam welded to the frame 82. The cap 83 is fixed to the semiconductor chip 10 with solder having good thermal conductivity in order to release the heat generated in the semiconductor chip 10.

The optical fiber connector 60 for inputting / outputting an optical signal to / from the semiconductor package as described above is made of a precision molded product made of resin, and a guide hole 61 is formed at a portion where the connector pin 51 is fitted. There is. Receptacle 5
By connecting the optical fiber connector 60 to 0, the optical element 30 and the optical fiber 70 are optically coupled. The connector pins 51 and the input / output pins 81 are inserted and removed in the same direction. The optical fiber 70 is made of quartz glass and has a diameter of 125 μm and a wavelength of 1.3 μm. The optical fibers 70 are bundled with a resin coating to form an optical fiber cable 71. The array pitch of the optical fibers 70 is 250 μm like the optical element 30 and the lens 41.

Next, an outline of the manufacturing process of the semiconductor package of this embodiment will be described below.

First, the semiconductor chip 10 on which the integrated circuit 11 is formed, the wiring substrate 20 on which the integrated circuit 21 is formed, and the optical element 30 are independently manufactured by a manufacturing method well known in the related art, and are inspected in advance. I'll do it. When the integrated circuit 21 and the optical element 30 are formed monolithically on the wiring board 20, it is necessary to match the forming process of the integrated circuit 21 and the optical element 30, but this is extremely difficult. Further, even after the formation, the optical element 30 is likely to deteriorate due to the difference in lattice constant between Si and the compound semiconductor. On the other hand, in the present embodiment, since the forming process suitable for each of the optical element 30 and the integrated circuit 21 can be selected, the reliability can be improved.

Next, a through hole is formed in the wiring board 20 by a processing method such as etching or dicing, and the optical element 30 is fixed in this through hole. Next, the wiring layer 22 is formed on the surfaces of the wiring board 20 and the optical element 30, and in this state, inspection is performed by a wafer prober or the like. Further, the semiconductor chip 10 is flip-chip connected to the wiring layer 22 by the solder bumps 12, and the TAB 23 is connected to the wiring layer 22.
Here, the chip 10 and the wiring board 2 through the TAB 23.
0, the optical element 30 is inspected.

The light propagating medium 40 is sealed and fixed in advance in the through hole provided in the package base 80.

Next, power is supplied to the wiring board 20 through the TAB 23, the optical element 30 and the lens 41 are aligned while driving the optical element 30, and the wiring board 20 is fixed to the package base 80. After that, the TAB 23 is connected to the package base 80, and power is supplied through the input / output pin 81 to inspect the optical coupling loss and the optical input / output characteristics of the optical element 30 and the lens 41. The receptacle 50 is a light propagation medium 40.
After being aligned with respect to, the package base 80 is fixed. Then, the optical fiber connector 60 is connected to the receptacle 50, and the optical coupling loss between the optical element 30 and the optical fiber 70 is inspected.

Next, the semiconductor chip 1 is placed in a dry N ₂ atmosphere.
0 and the cap 83 are fixed, and the cap 83 and the frame 8
2 is seam welded to seal the package. Finally, the optical fiber connector 60 is connected and the input / output pin 81
The electrical input / output characteristics, optical input / output characteristics, reliability, etc. of the semiconductor package are inspected by supplying power by

According to this embodiment, the package base 80
Via the optical transmission medium 40 and the optical fiber connector 60 of
The optical element 30 can be optically connected to the optical fiber 70 outside the package. That is, electrical signals from the integrated circuits 11 and 21 can be input / output as optical signals from the package base 80 by optical interconnection. This will make a 25x25 two-dimensional array
When a 4 x 4 unit optical interconnection is provided as a unit, the area of about 1 inch square of the package base is about 1
It is possible to input and output 0000 signal lines. In the case of the conventional semiconductor package to which the optical interconnection is not applied, the limit of the number of input / output signals by the TAB 23 and the input / output pin 81 is about 3000 to 4000. Therefore, by applying the present invention, it is possible to realize a significantly higher density connection than the conventional one, and it is possible to increase the number of inputs and outputs of the semiconductor package. Also, for optical interconnection, TA
Compared with electrical wiring using B23 and input / output pin 81, it has advantages such as high speed, wide band, and non-interference. By using a laser diode and a photodiode as in this embodiment, G
It is possible to input and output high-speed signals of the order of Hz or higher.

Further, since the receptacle for connecting the optical connector is provided on the bottom surface of the semiconductor package, the insertion / removal directions of the connector pin 51 and the input / output pin 81 can be made coincident with each other, which facilitates the mounting work on the wiring board. be able to. Moreover, since it is not necessary to provide a space for laying the optical fiber around the semiconductor package, the packaging density of the semiconductor package on the wiring board is not reduced.

Further, since the signal from the package base 80 can be taken out from both the optical input / output and the input / output pin, the optical signal or the electric signal can be selected according to the input / output specifications. For example, it is possible to select optical input / output for the high-speed signal wiring and select the input / output pin 81 for the power supply wiring.

Although laser diodes and photodiodes are used as the optical elements in this embodiment, other optical logic operation elements such as an optical bistable element and an optical thyristor element,
Alternatively, an OEIC element in which a drive circuit for an optical element, a signal multiplexing circuit, or the like is incorporated can be used.

Further, in the present embodiment, the optical element is embedded and fixed in the through hole provided in the wiring board, but a concave portion may be provided in the wiring board instead of the through hole and fixed therein. However, in this case, as the wavelength of the optical element, one that transmits the wiring substrate and the fixing material is selected.

Further, although the connector pin type is used for the optical fiber connector, a screw type, a plug-in type or the like may be used, or an assembly in which the optical fiber connector and the optical propagation medium are previously integrated is used. It goes without saying that it is good.

FIG. 2 is a partial sectional view of a semiconductor package according to the second embodiment of the present invention. In this embodiment, in the same semiconductor package as that of the first embodiment, the optical element 30 and the wiring board 20 are installed on the support substrate 90, and the support substrate 90
Are installed on the package base 80.

The optical element 30 has a planar electrode 33 connected to the wiring layer 22, and the p-type electrode and the n-type electrode are
Both are formed on the wiring layer 22 side. Support substrate 90
Is made of Si transparent to the wavelength of 1.3 μm of the optical element 30, and has a thermal conductivity about twice that of the material InP of the optical element 30. The support substrate 90 is used for the optical element 30 and the wiring substrate 2.
It is fixed with a thin and transparent adhesive. Also,
The support substrate 90 and the package base 80 are fixed by a heat conductive resin.

According to the present embodiment, the support substrate 90 can function as a heat sink, and the heat generated by the optical element 30 can be radiated through the support substrate 90. Therefore,
Compared to the case where the support substrate 90 is not provided, the temperature difference between the central portion and the peripheral portion of the optical element 30 can be reduced, and the characteristic variation and thermal crosstalk of the optical element 30 due to heat can be reduced.
The light emitted from the optical element 30 passes through the support substrate 90, and the input / output is not hindered. Further, the support substrate 90 can reinforce the fixation between the optical element 30 and the wiring board 20, and has an effect of preventing stress concentration on the bonding interface between the optical element 30 and the wiring board 20. Since the wiring substrate 20 and the support substrate 90 are both made of Si and have the same coefficient of thermal expansion, no thermal stress is generated.

The light emitted from the light emitting portion 31 of the optical element 30 is
Spread by diffraction. The refractive index n ₁ of the optical element 30, the distance t ₁ from the light emitting unit 31 to the supporting substrate 90, the emission wavelength λ, the spot size ω of the light emitting unit 31, the refractive index n of the supporting substrate 90.
₂ , the support substrate 90 and the package base 8 have a thickness t _2.
The spot size ω ′ at the interface of 0 is (λ / πω) · (t
It becomes about ₁ / n ₁ + t ₂ / n ₂ ). For example, in this embodiment, n ₁ = 3.2, t ₁ = 400 μm, λ = 1.3 μm
When m, ω = 1 μm, n ₂ = 3.5, and t ₂ = 500 μm, the spot size ω ′ is about 110 μm.

In the present embodiment, for example, by using the lens 41 having an effective aperture D of 230 μm and satisfying D ≧ 2ω ′, the light emitted from the light emitting section 31 can be effectively incident on the lens 41. Further, by setting the array pitch p of the light emitting units 31 to 250 μm and satisfying p ≧ 2ω ′, it is possible to prevent the crosstalk of the light emitted from the adjacent light emitting units 31. Although the above description is for the light emitting portion, the same effect can be obtained for the light receiving portion.

In this embodiment, the light incident on the lens 41 is coupled to the optical fiber 70 having a core diameter of 50 μm by the lens 41 having a radius of curvature of about 170 μm provided on the light propagation medium 40 having a thickness of about 5 mm. Even if the positions of the optical element 30 and the lens 41 are deviated by ± 10 μm in the manufacturing process, if the receptacle 50 is aligned with the accuracy of ± 10 μm and fixed to the package base 80, the coupling loss can be suppressed to −1 dB or less. You can That is, according to the present embodiment, it is possible to easily assemble the module by rough alignment work.

FIGS. 3 and 4 respectively show the third aspect of the present invention.
FIG. 7 is a partial cross-sectional view of the semiconductor packages of the example and the fourth example. These examples show an example of means for providing an optical element on a wiring board. In FIG. 3, the wiring board 501 is provided with a through hole 504.
The optical element 503 is fixed to the substrate 04 by resin or the like. Also,
In FIG. 4, the wiring board 511 is provided with a recess 514, and the optical element 513 is fixed to the recess 514 with resin or the like. The through hole 504 or the recess 514 provided in the wiring board 501 or 504 has a plane orientation (10
It is processed by anisotropically etching the Si crystal wafer of 0) with a KOH aqueous solution or the like. At this time, the plane orientation of the side surface of the through hole 504 and the concave portion 514 is (111).

By processing the through holes or the recesses provided in the wiring board by anisotropic etching as in the third and fourth embodiments, the accuracy is higher than that by machining.
For example, processing on the order of μm or less is possible. By increasing the processing accuracy, the accuracy of arranging the optical element on the wiring board is improved, so that the positioning accuracy of the optical element with respect to the optical propagation medium provided in the package base can be improved.

FIG. 5 is a partial cross-sectional view of the light propagation medium portion of the semiconductor package of the fifth embodiment of the present invention.

In this embodiment, unlike the first and second embodiments, a glass-made focusing rod lens 521 is used as the light propagation medium. The rod lens 521 has a diameter of 125 μm and an optical path pitch length of 0.25 μm.
Further, due to the impurity doping from the surface of the glass rod, the refractive index has a square distribution in the rod radial direction, and the refractive index at the central portion is about 1.6. A front spherical lens 522 having a radius of curvature of about 170 μm is formed of a buffered hydrofluoric acid solution at the tip of the rod lens 521 by utilizing the difference in etching rate due to the difference in the amount of impurities. Rod lens 521
A light shielding material 523 made of black glass is filled in between.

According to the present embodiment, it is possible to realize optical coupling with a lower loss than that of the second embodiment, and the optical element and the optical propagation medium,
Positioning work with the receptacle can be further simplified. For example, even if the positions of the optical element and the rod lens 521 are deviated by ± 10 μm, the receptacle should be ± 20 μm.
If they are aligned and fixed to the package base 80 with an accuracy of about m, an extremely low coupling loss of −0.5 dB or less can be obtained. Further, by using the light shielding material 523, there is an effect that the optical crosstalk can be further reduced as compared with the second embodiment.

FIG. 6 is a partial sectional view of a semiconductor module according to a sixth embodiment of the present invention.

The semiconductor module of this embodiment is one in which the semiconductor package as described in the first to fifth embodiments is mounted and connected on the wiring board 200.

The semiconductor package is the semiconductor chip 11.
0, the wiring board 120, and the package base 180. The semiconductor chip 110 is connected to the wiring board 120 by bumps 112, and the wiring board 120 is provided with an optical element 130 having a wiring layer common thereto. The package base 180 on which the wiring board 120 is installed is provided with an input / output pin 181 for inputting / outputting an electric signal to / from the light propagation medium 140 provided corresponding to the optical element 130. A receptacle 150 for connecting the optical fiber connector 160 is provided. Inside the semiconductor package, the cap 1
83, the frame 182, and the package base 182 are hermetically sealed.

On the other hand, the surface of the wiring board 200 is provided with an input / output pin connector 202 into which the input / output pins 181 are inserted, and the optical axis is perpendicular to the wiring board 200 and a gap is provided on the side surface. The optical fiber connector 160 is installed, and the optical fiber 170 is laid on the back surface of the wiring board 200. Wiring board 2
Reference numeral 00 is a multilayer printed wiring board in which low-resistance copper wiring is formed by using a low dielectric constant resin as a board material. The input / output pin connectors 202 are arranged by the support 201, and the ends thereof are soldered to the through holes formed in the wiring board 200. Optical fiber connector 160
Is a precision molded product of resin, and has a guide hole 161 into which a connector pin 151 provided on the receptacle 150 is fitted.
And a collar 162 are formed. The guide hole 161 is formed with a taper-shaped wide mouth portion, and the flange 162 and the back cover 2 are formed.
A spring 204 is provided between 03. The optical fiber cable 171 is a bundle of optical fibers 170, and is attached to the back cover 203 by a coating 205 made of a heat shrinkable tube.

According to this embodiment, the optical fiber connector 1
By mounting the semiconductor package on the wiring board 200 provided with 60, both electrical input / output and optical input / output can be easily taken out. Generally, higher precision is required for optical fiber connection than for input / output pin connection.
If the optical fiber connector 160 is rigidly fixed to the wiring board 200, the required accuracy cannot be achieved. Therefore, in this embodiment, the receptacle 150 is provided by the gap provided between the side surface of the optical fiber connector 160 and the wiring board.
Also, the mounting error of the input / output pin 181 and the input / output pin connector 202 can be absorbed. Since the guide hole 161 is provided with the tapered wide opening, the connector pin 151 can be easily inserted into the guide hole 161. Further, when the receptacle 150 and the optical fiber connector 160 are connected, the spring 204 acts on the insertion pressure, and when detached, the support body 201 uses the collar 201.
Since 62 is locked, the connector pin 151 and the input / output pin 181 can be inserted / removed at the same time. Coating 20
5 has an effect of preventing the optical fiber cable 171 from being broken near the back cover 203. By laying the optical fiber cable 171 on the back surface of the wiring board 200 in advance, a desired optical wiring can be obtained only by mounting the semiconductor package on the wiring board 200.

In this embodiment, one optical fiber connector is provided for one optical element, but an optical fiber connector for collectively connecting a plurality of optical fiber cables to a plurality of optical elements is used. It is also possible to provide. In order to further miniaturize the optical fiber connector, the optical element or the array pitch of the optical fibers may be narrowed to use a small diameter optical fiber. The back surface of the wiring board may be provided with a guide mechanism for laying the optical fiber cable with a predetermined length and curvature, and by providing a mechanism similar to the lock mechanism or the spring mechanism shown in this embodiment, The same effect as these can be obtained.

FIG. 7 is a top view of a semiconductor module according to the seventh embodiment of the present invention. In this embodiment, a plurality of semiconductor packages 300 are mounted and connected on the wiring board 350. Inside the frame 301 of the semiconductor package 300, for example, four semiconductor chips 310 each having an instruction processor circuit including a high-speed buffer storage circuit 311 and a semiconductor chip 3 having a system control circuit are formed.
20 is connected to a wiring board 330 made of a semiconductor wafer by bumps. Wirings formed on the wiring board 330 connect between the respective semiconductor chips. An optical element 331 is provided on the wiring board 330 immediately below the semiconductor chip 320 on which the system control circuit is formed, and a work memory circuit 332 is formed on the wiring board 330 around the wiring board 330. A multilayer wiring layer is formed on the surface of the wiring board 330, and this wiring layer is connected to the package base 302 by the TAB 340. Package base 3
02 has an input / output pin, a light propagation medium, and a receptacle, as shown in the first and sixth embodiments. On the back surface of the wiring board 350, an optical fiber connector and an optical fiber cable are provided at positions corresponding to the optical elements 331, and the plurality of semiconductor packages 300 are mutually connected by the optical fiber cable.

The optical element 331 comprises a two-dimensional array of surface emitting laser diodes or photodiodes. A 25 × 25 laser diode array 7 is provided on the wiring board 330.
And a 25 × 25 photodiode array. The laser diode array and the photodiode array are connected to the photodiode array and the laser diode array of another semiconductor module to which they are connected, respectively.
It is connected by an optical fiber cable of × 25 cores. The optical path lengths of the optical fiber cables and the optical propagation medium are equal, and the variation of the optical propagation time is within a predetermined range with respect to the circuit clock. The laser diode array and the photodiode array are alternately arranged in order to disperse the heat generated by the laser diode array.

FIG. 8 is a schematic diagram of a connection network between eight semiconductor packages 300 mounted on a wiring board 350 in the semiconductor module according to the seventh embodiment. Semiconductor chip 320 provided in each semiconductor package
The two are mutually connected by two sets of optical fiber cables 360 for transmission and reception. That is, a system of 32 processors is configured by a 72-byte full connection network. The total number of wirings between the semiconductor packages 300 is 70,000. Since the distance between the semiconductor packages 300 is at most several tens of cm, the transmission time between the system control circuits can be about 1 nsec when the optical fiber cable 360 having a refractive index of 1.5 is used. This value is sufficiently smaller than that of the conventional electric wiring, and it can be said that the optical fiber connection network of the present embodiment is also useful in a system whose machine cycle is on the order of nsec or less.

According to this embodiment, in the tightly coupled multiprocessor system, there is an effect that a complete connection network which cannot be realized by the conventional technique due to the input / output pin neck can be constructed. Such a complete connection network is the most ideal connection form in order to improve the performance of a multiprocessor system, and the optical interconnection can speed up the transmission time between the processors and the electrical wiring. As described above, there are advantages that the signal waveform is not deteriorated by the capacitance and that there is no problem of ground noise or crosstalk. In the present embodiment, various functional circuits and elements can be appropriately assigned to the semiconductor chip and the wiring board. For example, by arranging the optical element 331 near the system control circuit, the wiring delay time can be shortened. it can.

Although the complete connection network is constructed in the seventh embodiment, other connection networks may be constructed depending on the required system performance. For example, the number of optical fibers can be reduced by using an optical fiber coupler in which one optical element is branched and connected to a plurality of optical elements. In the seventh embodiment, the optical interconnection is applied to the connection between the tightly coupled processors, but it is naturally possible to be applied to the connection of the main memory circuit, the extended memory circuit, the input / output processor circuit, the loosely coupled multiprocessor and the like. .. In addition to the multiprocessor, it is clear that the effect of the present invention can be exerted in a device such as a massively parallel processor or a large capacity exchange that requires a super high density connection for connecting semiconductor packages.

As is well known, the semiconductor package and the semiconductor module can take various forms, but the present invention can be effectively implemented by adapting to each form.

[0071]

As described above, according to the present invention, in a semiconductor package including a semiconductor chip and a wiring board to which the semiconductor chip is connected, and a semiconductor module including a wiring board to which the semiconductor package is connected. Since high-density and high-speed optical interconnection can be implemented extremely practically, there is an effect that the performance of the semiconductor package and the semiconductor module can be improved. Especially high speed
It is clear that the effect of the present invention is remarkable because a large-scale information processing system including a highly integrated semiconductor package requires a huge amount of wiring.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor package according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a semiconductor package according to a second embodiment of the present invention.

FIG. 3 is a partial cross-sectional view of a semiconductor package according to a third embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of a semiconductor package according to a fourth embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of a semiconductor package according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of a semiconductor module according to a sixth embodiment of the present invention.

FIG. 7 is a top view of a semiconductor module according to a seventh embodiment of the present invention.

FIG. 8 is a schematic diagram showing a connection between semiconductor packages in a semiconductor module of a seventh embodiment of the present invention.

[Explanation of symbols]

10, 110, 310, 320 ... Semiconductor chip 20,
120, 330 ... Wiring board, 22 ... Wiring layer, 30, 13
0,331 ... Optical element, 40, 140 ... Optical propagation medium, 5
0, 150 ... Receptacle, 60, 160 ... Optical fiber connector, 70, 170 ... Optical fiber, 80, 180,
302 ... Package base, 81, 181: Input / output pins, 171, 360 ... Optical fiber cable, 200, 3
50 ... Wiring board, 202 ... Input / output pin connector, 30
0 ... Semiconductor package.

Claims (15)

[Claims] 1. A semiconductor chip, a wiring board on which the semiconductor chip is mounted, and a part of the wiring board, which inputs and outputs optical signals in a direction perpendicular to the other surface of the wiring board. An optical element, a package base that mounts the wiring board, and has a light propagation medium at a position corresponding to the optical element; and a package base that is connectable to an optical fiber cable, the light propagation medium and the optical fiber. A semiconductor package having a receptacle for optically connecting to a cable. 2. The semiconductor package according to claim 1, wherein the optical element is provided in a through hole or a recess formed in the wiring board. 3. The semiconductor package according to claim 1, wherein the wiring board has a wiring layer for connecting a circuit formed on the wiring board or on the semiconductor chip to the optical element. package. 4. The semiconductor package according to claim 1, wherein the semiconductor chip is flip-chip connected to the wiring board, and the optical element is provided in the vicinity of the semiconductor chip. 5. The semiconductor package according to claim 1, wherein the light propagation medium has a lens or an optical waveguide element corresponding to the optical element. 6. The semiconductor package according to claim 1, further comprising a support substrate provided between the wiring substrate and the package base. 7. The semiconductor package according to claim 6, wherein the support substrate is made of a material having a good transparency to a wavelength of light emitted from the optical element and a good heat conduction characteristic. A semiconductor package characterized by the above. 8. The semiconductor package according to claim 7, further comprising a lens near an interface between the package base and the supporting substrate, wherein the optical element has a refractive index n ₁ and a light emitting portion or a light receiving portion of the optical element. The distance to the supporting substrate is t ₁ , the emission wavelength or the receiving wavelength of the optical element is λ, the spot size of the light emitting portion or the light receiving portion is ω, and the refractive index and the thickness of the supporting substrate are n ₂ and t ₂ , respectively. , Where D is the aperture of the lens, πDω / 2λ ≧ t
A semiconductor package characterized in that a relationship of ₁ / n ₁ + t ₂ / n ₂ is established. 9. The semiconductor package according to claim 7, wherein the optical element has an array of a plurality of light emitting portions or light receiving portions, the refractive index of the optical element is n ₁ , and the light emitting portion or the light receiving portion extends from the optical element. The distance to the supporting substrate is t ₁ , the emission wavelength or the receiving wavelength of the optical element is λ, the spot size of the light emitting portion or the light receiving portion is ω, the array pitch is p, and the refractive index and the thickness of the supporting substrate are n. ₂ and t ₂ , πpω / 2λ ≧ t ₁ / n ₁ + t ₂ /
A semiconductor package characterized in that a relationship of n ₂ is established. 10. A semiconductor chip, a wiring board on which the semiconductor chip is mounted on one surface, and a part of the wiring board, which inputs and outputs optical signals in a direction perpendicular to the other surface of the wiring board. An optical element and the wiring board mounted on one surface thereof, and an optical transmission medium provided at a position corresponding to the optical element and an input terminal provided on the other surface for inputting / outputting an electric signal to / from the wiring board. A package base with output pins,
A receptacle that is provided on the package base so as to be connectable to an optical fiber cable and that optically connects the optical propagation medium and the optical fiber cable, and mounts the wiring board on one surface and the optical fiber on the other surface. A semiconductor module comprising: an input / output pin connector in which fibers are laid, and the input / output pins are inserted; and a wiring board having an optical fiber connector for connecting the optical fiber to the receptacle. 11. The semiconductor module according to claim 10, wherein the receptacle has a connector pin that fits into a guide hole provided in the optical fiber connector, and the connector pin has the input / output pin as the input / output. A semiconductor module configured to be inserted into the guide hole at the same time as being inserted into a pin connector. 12. The semiconductor module according to claim 11, wherein the guide hole has a tapered wide opening. 13. The semiconductor module according to claim 10, wherein the wiring board has a spring mechanism that holds the optical fiber connector against pressure when connecting the optical fiber connector and the receptacle, and the optical fiber. A semiconductor module comprising: a connector and a lock mechanism that holds the optical fiber connector against pressure when the receptacle is removed. 14. A semiconductor module having a plurality of semiconductor packages mounted on a wiring board, each of the semiconductor packages having a plurality of integrated circuit chips forming an instruction processor and a system control circuit, and mounting the integrated circuit chips. A wiring board, an optical element provided on a part of the wiring board and connected to the integrated circuit chip or a circuit formed on the wiring board by a wiring formed on the wiring board, and the wiring board is mounted. A package base having an input / output pin for inputting / outputting an electric signal to / from the optical propagation medium and the wiring board at a position corresponding to the optical element, and provided on the package base so as to be connectable to an optical fiber cable, The wiring board has a receptacle for optically connecting the optical transmission medium and the optical fiber cable, and the wiring board Corresponding to each of the packages, an input / output pin connector into which the input / output pin is inserted and an optical fiber connector for connecting the optical fiber to the receptacle are provided, and a space between the semiconductor packages is provided on a back surface of the wiring board. A semiconductor module characterized by being connected by an optical fiber cable provided. 15. The semiconductor module according to claim 14, wherein each of the optical elements has a plurality of light emitting elements and light receiving elements, and the optical propagation medium and the optical fiber for connecting the respective light emitting elements and the light receiving elements are connected. A semiconductor module in which the optical path lengths are equal to each other.